PEORIA — By day Alan Kenworthy is a large track-type tractor engineering technical steward for Caterpillar Inc., but by night he is a trombone player.

And he doesn’t even need to change out of his work clothes to go from engineer to musician.

Employing thousands of people in the Peoria area, Caterpillar has become somewhat of a community of its own. In 1978, an engineer by the name of Scott Rodibaugh and a production worker, John “Mark” Russell, felt this community was lacking a jazz group. Thus, the Caterpillar Employees Big Band was established, with Russell serving as the group’s original musical director.

To this day, the group continues to carry on the tradition, sharing its talent within the company and beyond.

The Caterpillar Employees Big Band is a traditional jazz band with 18 members — five saxophones, four trombones, four trumpets, a guitar, double bass, piano, drums and featured vocalist. When performing they can often be found in yellow or black, more often than not wearing some type of CAT-branded gear.

While their outfits change each season, not much else has over the past 41 years. As a founding member and musical director of the ensemble for the past 12 years, the main goal — in Kenworthy’s eyes — has always been to help keep jazz music of the 1930s, '40s and '50s alive.

Kenworthy has been playing the trombone for as long as he can remember. In 1977, one year after college, Kenworthy started working with Caterpillar and in 1978, the Caterpillar Employees Big Band was formed. He has been with the band since its inception and has no plans to stop.

“I just love it,” said Kenworthy.

Kenworthy played piano for the band for some time until a “better player” joined and he returned to his primary position in the trombone section. That better player was Brian Havlisch.

Havlisch has been a software engineer for Caterpillar for the past five years. He learned about the group his first day on the job and has been playing with them ever since. He started off as a substitute when the group needed the extra hands and eventually worked his way to full-time piano player.

“It’s a unique opportunity to express creativity outside of the day to day job, especially for engineers,” said Havlisch. “It’s a good escape and I could not think of a better way to spend my free time.”

The group meets every Thursday evening to practice. Although it has seen much turnover throughout its many years, Kenworthy believes that a love for jazz music will always attract new members and an eager audience. To Kenworthy, nothing compares to seeing the group click during their performances.

“That’s the magic of live music,” he said.

Considering the group has a mixed level of musical background, the weekly practices allow for better live experiences because members have an opportunity to play without pressure. Once they hit the stage Kenworthy said feeling each member on the same wavelength is a “great experience” and makes performing “really fun.”

They started performing at company events, eventually picking up various gigs in the area, taking any opportunity they are given to perform. Their staple performance includes Kenworthy and Havlisch’s favorite, the Metamora summer concerts in the park. They both said they can always count on a nice crowd.

Their next performance will be at 6:30 p.m. Thursday, July 18, at Idlewood Park in Morton.

Music is a big part of all of the members' lives and the commitment that they and those before them have made is evidence that music is meaningful to them. Yet, to Havlisch, it’s camaraderie that makes all the difference.

“There are people from all different walks of life in this band,” said Havlisch. “You get to see people you don’t see everyday ... it really reaches every part of the company.”

Grace Barbic can be reached at gbarbic@pjstar.com or at (309) 686-3194. Follow her on Twitter @gracebarbic.